Too small for what? If all they are doing is gaming and sex, they really only need the area of the bed and somewhere to stash clothes overnight. This is a status/power play from them. You are absolutely correct to tell them to take a long walk off a short pier. It is your house after all. If their personal pride calls them to do the full Karen, they should go to a hotel and pay the staff to pander to their egos. The price of which is usually high. If they want to avoid first class hotel charges, it’s up to them to adapt to the accommodation available.
Champagne tastes on a beer budget are rightly the source of much comedy, and deserved ridicule.